POS1336 MRI DIGITAL ARTERY VOLUME INDEX (DAVIX©) AS QUANTITATIVE, CONTINUOUS IMAGING OUTCOME MEASURE OF VASCULAR DISEASE IN SYSTEMIC SCLEROSIS
Authors: M. Hughes, S. Di Donato, K. Gjeloshi, G. Abignano, F. Danzo, G. Lettieri, E. De Lorenzis, D. Bertham, P. O’connor, O. Kubassova, J. Dehmeshki, F. Del Galdo
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> In Systemic Sclerosis, beyond the value of Nailfold capillaroscopy, there is still a deeply unmet need in quantitative imaging surrogate outcome measures to assess activity and/or severity of peripheral vascular disease. This has been halting the implementation of trials targeting vascular disease beyond crude endpoints such as number of digital ulcers (DU). Quantitative MRI based scores have boosted the implementation of new trials in inflammatory arthritis. <h3>Objectives</h3> To determine the value of MRI-based Digital Artery Volume Index (DAVIX©) score in predicting the burden of DU disease as well as other vascular endpoints including clinical manifestation and patient reported outcomes (PROs). <h3>Methods</h3> Consecutive patients with Raynaud's phenomenon were enrolled in two independent discovery and validation cohorts. Data collected included: pulmonary function tests, nailfold capillaroscopy, modified Rodnan Skin Score (mRSS), history/presence of DU (defined as DU Disease), sHAQ-DI, Cochin hand function and Borg scales. Discovery cohort had clinical follow up data at 12 months, Validation cohort had only baseline data. DAVIX© (dominant hand) was calculated by MRI time of flight based, digital artery volumetric assessment over the volume of each finger, as %mean of the 4 fingers [1, 2]. Mann-Whitney test was used to compare DAVIX© between patients' subgroups. Correlations between DAVIX© and clinical variables/PROs were performed using Pearson's and Spearman's tests, as appropriate. Data analysis was conducted using R software. <h3>Results</h3> 233 patients were recruited in discovery (D=91) and baseline validation (V=142) cohorts. 139 patients fulfilled 2013 SSc classification criteria (62 in discovery cohort and 77 in validation cohort), 94 were patients with VEDOSS (2013 ACR/EULAR SSc classification criteria &lt;9) and not included in further analysis. Median (IQR) disease duration was 5.9 (7) and 4.7 (6) years in the two cohorts (P=0.618). DAVIX was significantly lower in patients with DUs disease in both cohorts (0.34% and 0.49% vs 0.65% and 0.75%) compared to patients with no DUs (D, P=0.0018; V, P=0.003). DAVIX© correlated with baseline DLCO% in both cohorts (r= 0.368 and 0.315; P=0.004 and 0.038, respectively). There was no correlation with mRSS or FVC% whereas, DAVIX© correlated with FVC/DLCO ratio (r=-0.337, P=0.009). The analysis of PROs showed that DAVIX correlated best with VAS DUs (r=-0.291 and -0.243, P&lt;0.05 for both cohorts) and VAS Raynaud (r=-0.270, P=0.048 for the discovery cohort), whereas there was no significant correlation with the other PROs. Importantly, DAVIX© correlated inversely with disease duration in both cohorts (r=-0.415 and -0.441, P&lt;0.001 for both). In the discovery cohort, 12 patients developed new (7) or their first (5) DUs during follow-up and their mean DAVIX© was 0.23% vs 0.66% of 73 patients who did not develop any new DUs (p=0.02). Standard Receiver Operating Curve indicated that DAVIX© &lt;0.36% conferred a 4 times higher risk of new DUs, independently of any other clinical variable. <h3>Conclusion</h3> DAVIX© is a feasible, automated, contrast-free imaging outcome measure that reflects worse vascular disease as far as DU disease, DLCO% and patient reported burden of Raynaud's and DU disease. DAVIX© validation in Randomized Controlled Trials would offer a novel imaging based surrogate outcome measure of vascular disease in Systemic Sclerosis. <h3>References</h3> [1]Allanore Y, Seror R, Chevrot A, et al. Hand vascular involvement assessed by magnetic resonance angiography in systemic sclerosis. Arthritis Rheum 2007; 56: 2747–54. [2]Zhang W, Xu JR, Lu Q, et al. High-resolution magnetic resonance angiography of digital arteries in SSc patients on 3 Tesla: preliminary study. Rheumatology (Oxford) 2011; 50: 1712–9. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Mike Hughes: None declared, Stefano Di Donato: None declared, Klodian Gjeloshi: None declared, Giuseppina Abignano: None declared, Fiammetta Danzo: None declared, Giovanni Lettieri: None declared, Enrico De Lorenzis: None declared, Dominic Bertham: None declared, Philip O'Connor: None declared, Olga Kubassova Employee of: Employee of Image Analysis Group, Jamshid Dehmeshki Employee of: Employee of Image Analysis Group, Francesco Del Galdo: None declared.